Method and Apparatus for Manufacturing Coated Profile Members

ABSTRACT

A method for manufacturing coated profile members ( 10 ), wherein a foil ( 16, 36 ) is cut to a predetermined width and wrapped around the profile member so as to form a butt seam extending in a longitudinal direction of the profile member, characterised in that the foil ( 16, 36 ) is cut by means of a cutting beam ( 24 ) in a condition in which an edge strip of the foil projects beyond the profile member ( 10 ), while a face of the profile member is used as reference for the position of the cutting beam.

The invention relates to a method for manufacturing coated profilemembers, wherein a foil is cut to a predetermined width and wrappedaround the profile member so as to form a butt seam extending in alongitudinal direction of the profile member, as well as an apparatusfor carrying out this method.

Methods of this type are employed especially for furniture profiles butalso for manufacturing door frames, door leaves, window profiles and thelike and have the purpose to coat a profile member, e.g. a chipboard oran MDF board, with a decorative foil, e.g., a plastic foil. In thisprocess, the profile member shall be wrapped in at least one foil websuch that neither an overlap nor a gap is produced at the positionswhere the edges of the foil webs abut against one another. This impliesthat the foil web is precisely cut to a suitable width.

Up to now, this is done by first bonding the foil onto the surface ofthe profile member and then milling away an edge strip of suitable widthfrom the foil that adheres to the surface of the profile member adjacentto a butt seam which extends, for example, in a certain distance from anedge of the profile member. This method has the drawback that the dustthat is produced in the milling process is likely to causecontaminations and other problems. In particular, dust particles maystick to the adhesive layer on the foil that has not yet been bondedonto the profile member, so that ugly pimples are produced when the foilis bonded. Moreover, the milling tool may be soiled by rapidly curingadhesive.

It is an object of the invention to provide a method and an apparatuswhich permit to neatly and precisely coating profile members with afoil.

In order to achieve this object, according to the invention, the foil iscut by means of a cutting beam in a condition in which an edge strip ofthe foil projects beyond the profile member, while a face of the profilemember is used as reference for the position of the cutting beam.

The cutting beam is preferably a laser beam. Optionally, however, awater jet or a plasma beam may also be used, for example.

When a reference face of the profile member is gauged, such a beam canbe used for producing a clean cut which extends exactly in longitudinaldirection of the profile member. During cutting, the edge strip of thefoil does not need to be supported on a substrate but projects freelyfrom an edge of the profile member. Moreover, since the cut is performedwith a cutting beam, there will be no contact between a cutting tool andthe foil which is generally coated already with an adhesive.Consequently, there is no contamination of the cutting tool withadhesive, and there is no risk that the foil will stick to the cuttingtool and will thereby be distorted or disturb the formation of a cleancut. After the foil has been cut to suitable width, the projecting edgestrip of the foil web is wrapped around the profile member and finallybonded thereto. Since the profile member has been gauged and the cuttingbeam is positioned with high precision, the width of the projecting andcut edge strip may be controlled such that a clean butt seam is formedafter the foil has been wrapped around the profile member.

It turns out to be particularly advantageous that, in this method, thesurface of the profile member is not needed for supporting the foilduring the cutting process. This opens the possibility, for example, tocoat individual profile members with an endless foil web in a continuousprocess, wherein certain gaps are left between the successive profilemembers, which gaps are only bridged by the foil. In contrast toconventional procedures where the profile members succeed one anotherwithout gaps therebetween and the foil connecting them is torn off alongthe butting ends in order to separate the profile members from oneanother, the method according to the invention permits to cleanly cutthrough the foil bridges that connect the successive profile members.

Useful details and further developments of the invention are indicatedin the dependent claims.

Embodiment examples will now be explained in conjunction with thedrawings. wherein:

FIGS. 1 to 6 show schematic cross-sectional views of a profile member indifferent stages of a process of coating it with a foil in accordancewith the method according to the invention;

FIG. 7 a schematic longitudinal section of the ends of two profilemembers which are held together by the foil wrapped around them;

FIG. 8 a schematic sectional view of a profile member for illustrating amodified embodiment of the method according to the invention; and

FIG. 9 a butt seam of a profile member that has been coated inaccordance with the method shown in FIG. 8.

In FIG. 1, a profile member 10, e.g. a door leaf formed by a chipboardor an MDF board, is advanced in the direction normal to the plane of thedrawing along a transport path 14 formed by rollers 12. An endless webof a foil 16 has a width that is somewhat larger than the width of thebottom side of the profile member 10 and is provided with an adhesivelayer 18 on its top side. The foil 16 is banded to the bottom side ofthe profile member 10 by means of the rollers 12 while rollers 20provide a necessary back pressure on the top side of the profile member.

In the example shown, the profile member 10 is formed with a rebate 22on both sides, and the foil 16 is bonded in such a position that itprojects beyond the rebate on both sides.

In FIG. 2. the profile member that is coated on one side with the foil16 passes through a cutting station where the projecting edge strips ofthe foil 16 are cut to a suitable width by means of cutting beams 24that are generated by laser cutting heads 26. The cutting heads 26 movealong the edges of the foil 16 that freely project beyond the profilemember 10 without contact between the cutting heads and the foil, andthey perform a cut which extends precisely in longitudinal direction ofthe profile member 10.

The cutting heads 26 are rigidly connected to callipers 28 each of whichgauges a lateral face of the profile member 10, a face of the rebate 22in the example shown. For example, the calipers 28 are elasticallybiased against the lateral edges of the profile member by means ofsprings 30, and, in order to reduce friction, they roll over the lateralface of the profile member with rollers 32.

In this way, the face of the rebate 22 which extends at right angles tothe foil 16 serves as a positional reference for the cutting edge 24, sothat the projecting width of the foil can be controlled with highprecision. In the example shown, this projecting width has been selectedsuch that it corresponds exactly to the face of the rebate 22 thatextends at right angles to the plane of the door leaf.

In a subsequent process step, shown in FIG. 3, the projecting edgestrips of the foil are bent over by means of rollers 34 and are pressedagainst the internal faces of the rebates 22. Thanks to the precisepositioning of the cutting heads 26, the foil will then reach exactly tothe internal corner of the rebate, thereby forming a butt seam with thebroader part of the profile member 10.

In a next step, as is shown in FIG. 4, another foil 36 is bonded to thetop side of the profile member 10, and the edges of the foil thatproject on both sides are bent by means of rollers 38 and are bonded tothe lateral faces of the profile member. The width of the foil 36 hasbeen selected such that it projects significantly beyond the lateralfaces of the profile member in the vicinity of the rebates.

FIG. 5 illustrates another cutting station where the projecting edgestrips of the foil 36 are cut to a desired width by means of cuttingbeams 24 of laser cutting heads 40. The cutting heads 40 are rigidlysecured to brackets 42 which are in turn rigidly connected to a commonaxle 44 of the rollers 20 which serve for bonding the foil 36 to the topsurface of the profile member 10. A suitable mechanism, which has notbeen shown, biases the axle 44 elastically against the transport path 14(which has only been shown in FIG. 1). Thus, the top surface of theprofile member 10 is gauged by the rollers 20 and serves as a positionalreference for the cutting beams 24. The height of the cutting heads 40has been selected such that the widths of the projecting edge strips ofthe foil 36 are each reduced to a width that corresponds to the width ofthe faces 26 of the rebates 22 that extend in parallel with the plane ofthe door leaf.

FIG. 6 shows the final condition in which the projecting edge strips ofthe foil 36 have been bent and bonded into the rebates 22. It can beseen that the edges of the foils 16 and 36 form precise butt seams 48 inthe internal corners of the rebates 22.

Since, in each of the cutting processes shown in FIGS. 2 and 5, asurface of the profile member 10 is gauged and serves as a reference forthe position of the cutting beam 24, the method is robust against anypossible dimensional or positional tolerances of the profile members.

FIG. 7 shows, in a longitudinal section, two profile members 10 whichare fed along the transport path 14 and have been coated with the foils16 and 36 by means of the process illustrated in FIGS. 1 to 6, whereinthe foils 16, 36 have been supplied as endless webs. It can be seen thatthe end faces of the two profile members 10 are separated from oneanother by a certain gap 50. They are however held together by thecontinuous foils 16 and 36. The gaps 50 permit to neatly separate theindividual coated profile members 10 from one another by cutting throughthe foil bridges formed between them. Since the edge strips of the foils16 and 36 project freely from the profile members, anyway, when they arecut with the cutting beams 24 (FIGS. 2 and 5), the gaps 50 between theindividual profile members do not hamper the cutting process.

FIG. 8 illustrates a modified embodiment of the method, wherein aprofile member 10′ which in this case has a simple rectangular crosssection is coated with a single foil 16. Here, the cutting beams 24 areused for cutting the projecting edge strips of the foil to such a widththat they form a single butt seam at the bottom side of the profilemember 10′ after they have been folded over.

The cutting station shown in FIG. 8 is different from the cuttingstation shown in FIG. 5 mainly in that the rigid brackets 42 have beenreplaced by actuators 52 that are controlled by a control system 54 suchthat the heights of the two cutting heads 40 relative to the profilemember 10′ are varied precisely in opposite sense. For example, thecutting heads 40 perform a sinusoidal oscillation in vertical direction.After the cut edge strips of the foil 16 have been bent over, they forma sinusoidal butt seam 48′ as shown in FIG. 9. Depending on thedecorative pattern on the foil 16, such an oscillating shape of the buttseam 48′ may be useful for making this seam less visible.

As an alternative, the two cutting heads 40 may be coupled to oneanother mechanically and may be driven by a common actuator.

1. Method for manufacturing coated profile members (10; 10′), wherein afoil (16, 36) is cut to a predetermined width and wrapped around theprofile member so as to form a butt seam (48; 48′) extending in alongitudinal direction of the profile member, characterised in that thefoil (16, 36) is cut by means of a cutting beam (24) in a condition inwhich an edge strip of the foil projects beyond the profile member (10,10′), while a face of the profile member is used as reference for theposition of the cutting beam.
 2. Method according to claim 1, forplate-shaped profile members (10), characterised in that a first foil(16) is applied on one side of the profile member and a second foil (36)is applied on the opposite side of the profile member such that the twofoils form two butt seams (48) with one another.
 3. Method according toclaim 2, characterised in that the butt seams (48) are formed in rebates(22) of the profile member (10).
 4. Method according to any of thepreceding claims, characterised in that the foil (16) or one of thefoils is cut while its projecting edges extend in parallel with acentral portion of the foil, and in that the side faces of the profilemember (10) that extend at right angles to the central portion of thefoil serve as the reference.
 5. Method according to any of the precedingclaims, characterised in that the foil (36) or one of the foils is cutin a condition where its projecting edges are bent relative to thecentral portion of the foil and engage side faces of the profile member(10; 10′) that extend at right angles to said central portion, and inthat a surface of the profile member that extends in parallel with thecentral portion of the foil serve as the reference.
 6. Method accordingto any of the preceding claims, characterised in that a plurality ofprofile members (10) are successively advanced on a transport path (14),with gaps (50) formed between the profile members, and are coated withthe foil (16, 36) that is supplied in the form of an endless web, sothat the individual profile members (10) are held together by foilbridges.
 7. Method according to any of the preceding claims,characterised in that the positions of the cutting beams (24) that areused for cutting the edges of the foil (16) that belong to one and thesame butt seam (48′), relative to the reference surface of the profilemember (10), are varied synchronously so as to form a meandering buttseam (48′).
 8. Apparatus for manufacturing coated profile members (10;10′), comprising a cutting tool (26, 40) for cutting a foil (16, 36) toa predetermined width, and an applicator member (34, 38) for wrappingthe foil, around the profile member so that an edge of the foil (16, 36)forms a butt seam (48; 48′) extending in a longitudinal direction of theprofile member, characterised in that the cutting tool is beam cuttinghead (26, 40) adapted to generate a cutting beam (24) and arranged tocontactlessly cut the foil (16, 36) by means of the cutting beam (24) ina condition in which an edge strip of the foil projects beyond theprofile member (10, 10′), and calliper means (28; 44) are arranged togauge a face of the profile member, so that this face serves as areference for the position of the cutting beam.